The major discovery this year are as follows. 1. Showed that radiation attenuated sporozoites administered intravenously into NHP induced potent CD4 and CD8+ T cell responses in blood and liver. Established that a high frequency of NK cells in the liver secrete IFN-g in response to stimulation providing an additional effector cell for protection. Furthermore, showed that monocytes and dendritic cells present SPZ antigen to T cells. 2. Completed a phase I clinical trial assessing whether irradiated PfSPZ given by the IV route is safe and protective in a dose escalation study. 3. Showed that an attenuated malaria vaccine ( PfSPZ Vaccine) confers high level protection in humans following an experimental challenge with malaria infection. 4. Showed that the dose of the PfSPZ Vaccine is critical for mediating immunity and protection.